insert into data di mysql

permisi mau tanya ini kenapa ya kok datanya gak mau masuk di database padahal tidak ada error

<?php

 $link = mysqli_connect("localhost","root","","admin_db");

 if($link === false){
 	die("ERROR: gak koneksi ke db gan!".mysqli_connect_error());
 }

 $judul = mysqli_real_escape_string($link, $_POST['judul']);
 $tanggal = mysqli_real_escape_string($link, $_POST['tanggal']);
 $jam = mysqli_real_escape_string($link, $_POST['jam']);
 $foto = isset($link, $_FILES['foto']['tmp_name'])? $_FILES['foto']['tmp_name']:null;
 $diskripsi = mysqli_real_escape_string($link, $_POST['deskripsi']);

 $namafolder="avatar/";
	if(!empty($_FILES['foto']['tmp_name']))
	{
		$jenis_gambar=$_FILES['foto']['type'];
		if($jenis_gambar=="image/jpeg" || $jenis_gambar=="image/jpg" || $jenis_gambar=="image/gif" || $jenis_gambar=="image/png")
		{
			$file =  $namafolder . basename($_FILES['foto']['name']);
			if(move_uploaded_file($_FILES['foto']['tmp_name'],$file)){

			 $sql = "INSERT INTO seminar (judul, tanggal, jam, foto, deskripsi) VALUES ('$judul', '$tanggal', '$jam', '$foto', '$diskripsi')";
			 if (mysqli_query($link, $sql)) {
			 	echo "succes gan silakan di cek!";
			 } else{
			 	echo "ERROR: error gan".mysqli_rror($link);
			 }
		  }
		}
	}

?>